Function FindChild

be/src/exec/orc/orc-column-readers.cc:399–413

* 'parent' is a complex type that might have multiple children, i.e. STRUCT or MAP. * 'descendant_col_id' refers to an ORC type somewhere under 'parent' in the type * hieararchy. This method selects the direct child of 'parent' that is also the ancestor * of 'descendant_col_id'. Return the result in '*child' and its index in '*field'. * Returns false for not found. */

 * Returns false for not found.
 */
bool FindChild(const orc::Type& parent, uint64_t descendant_col_id,
    const orc::Type** child, int* field) {
  DCHECK(parent.getKind() == orc::TypeKind::STRUCT ||
         parent.getKind() == orc::TypeKind::MAP);
  int size = parent.getSubtypeCount();
  for (int c = 0; c < size; ++c) {
    const orc::Type* node = parent.getSubtype(c);
    if (node && IsDescendant(*node, descendant_col_id)) {
      *child = node;
      *field = c;
      return true;
    }
  }
  return false;
}

void OrcStructReader::CreateChildForSlot(const orc::Type* curr_node,
    const SlotDescriptor* slot_desc) {